Lookleft, PM&C have the capability to fix the CASA mess, most probably by rewriting the Act, adopting an FAA template, terminating CASA and making people reapply for positions in two new organisations.
However as leadsled wrote, the Government first needs to authorise such a project - which they won't do unless forced by a catastrophic accident or serious well thought out pressure applied by GA industry (negative political advertising in marginal seats).
Note also that Qantas, Virgin, etc. don't care about CASA. The airlines have too much political pull and CASA hasn't had the technical capacity to regulate the major airlines since at least as long ago as my time - 1976.
I confirmed that with a big airline 'driver" a few months ago. CASA asks to see something about something e.g. iPads in cockpit, the airline just tells CASA technical BS that they don't understand and they go away again for another two years.
CASA is more at home prosecuting little fish like Gyrocopter and Jabiru pilots.